1. Field of the Invention
This invention relates to tools and more particularly to a layout tool or gauge for rolled metal H beams and the like, and has for its object the provision of an improved layout tool having orthogonal edges and surfaces which may be used to lay out points on the web and flanges of a beam. Points laid out on the web of a beam are scribed at the same distance from the outside face of the beam flange and tolerance of the flange angle is determined without requiring separate measurements at each location.
2. Description of the Prior Art
Structural steel fabrication requires the placing of chalk lines on non-uniform rolled shapes from specific points and working lines. The purpose of these chalklines is to locate holes and other details for later drilling, cutting, punching or welding. In the normal fabrication process, after the holes and details have been located, as a manner of quality control, these dimensions must be checked quickly and reliably.
In shop drawings which set out the dimensions on non-uniform rolled shapes, the shapes are treated as being perfect. In actuality, the material as produced is non-uniform in that one of the beam flanges may be slanted such that the flanges are non-parallel and non-perpendicular to the web surface on which points and working lines must be scribed. For these reasons, all dimensions are taken to a known point or line on a rolled section which is located on the outside surface of a flange at a point which intersects with the center line of the web.
Heretofor, layout tools for rolled metal H beams take the form of a hand held straight edge having a channel clearance for the end flange. One such layout tool is shown and described in U.S. Pat. No. 1,826,807. The tool shown and described in the foresaid patent takes the form of a thin strip of metal one end of which is pressed against the point to which all dimensions are taken. The other end of the tool, that is, the end which extends along the surface of the web, is provided with suitable scale markings and indicia and is held against the surface. It should be readily apparent that a tool of this nature occupies both hands of a worker and an additional worker is necessary to scribe any necessary measurement lines because of instability of the tool. Further, inasmuch as the tool comprises a fixed rule portion, it can only be used for certain size beams wherein the width of the web is greater than the length of the rule.